Stoker controlling system



Jan. 19, 1943. W. w. HALLINAN 2,308,507

sToKER CONTROLLING SYSTEM Filed Dec. l. 1939 4 Sheets-Sheet l Jan. 19, 1943.

w. w. HALLINAN 2,308,507

S TOKER CONTROLLING SYS TEM Filed Dec. 1, 1939 4 sheets-sheet? Jan. 19, 1943. W. w. HALLvlNAN i 2,308,507

STOKER CONTROLLING SYS TEM Filed Dec. l, 1939 106 '102 g 702]305 mi 125 4 Sheets-Sheet 5 Jan. 19, 1943. w. w. HALLINAN STOKER CONTOLLING SYSTEM Filed Dec. l. 1939 4 Sheets-Sheet 4 the air supply for combustion of degrees in' the, devices only in the over-run that wasted on account of Patented Jan. 19, 1943 2,308,501 sroKER ooN'rRoLLlNG |sir-STEM William W. Hallinan, Mendota, Ill. Application December 1, 1939, serial No. 307,056

(o1. 23e-1o) i 20 Claims.

The present invention relates to stoker controlling systems, and is particularly concerned with stoker systems including controlling` devices which are adaptable for use in all kinds of coal stoker furnaces and heating systems, whether they be hot air, hot water, steam, or vapor.

One of the objects of the invention is the provision of an improved coal stoker system which is adapted to provide for the anticipation of the amount of heat needed, responsive to any room demand. and to provide a heat, without the over-.run of temperature which sufficient amount of occurs with the coal stoker systems of the prior art. In order to point out particularly the advantages of the present invention, a comparison with the structures and disadvantages of the prior artcoal stoker systems is necessary, asy

follows.

In the standard coal stokers of the prior art the stoker feed is usually set at a given coal feed, such as, for example, fifty pounds per hour, and

the coal is manually adjusted for this predetermined feedAof coal. The feed of coal by the stoker is turned on when the room thermostat closes an electric circuit and calls for heat, the electric circuit from the thermostat energizing the stoker feed motor through suitable relays.

The stoker operates in this predetermined manner with the feed of a predetermined amount f of coal per hour, and the supply of air at a xed rate, as long as the room thermostat calls for heat. When the temperature in the room has risen to such a value that the thermostatic switch in the room is opened, that is, when the thermostat is satisfied, the opening of the `circuit at the thermostat de-energiz'es the motor through suitable relays and stops the stoker in the devices of the prior art. Then a large amount of burning coal is inthe furnace, which con. tinues to produce heat'in greater quantity than can beused, and it of course, impossible to prevent this further production of heat by the coal bedin the furnace, and the room`temperature is over-run ordinarily from ten to fteen of the prior art.

This means uneven fort in the home, and much coal is wasted not is brought about by such devices of the prior art', but the coal is also the increased consumption offcoal when a stoker/ is operated in this manner. Furthermore, when the stokers of the prior art operated in this manner, with a. manual adjustment of the air supply, and the stoker was shut temperature and discom-f the furnace.l

run of the temperature,

down, there was practically no air delivered to burn the coal which has just entered 'the furnace and was being ignited by the bed of coals'. Therefore, in the devices of the prior art, the furnace smokes badly and lcovers the heating surfaces with soot. Of course, the covering of the heating surfaces with soot prevents the most ef- -cient transfer of heat from the combustion gases to thel walls of the furnace or to the water in the boiler, and the soot must be cleaned out, and the soot also represents Waste, on account of the fact that it is the product of incomplete combustion.

The stokers of the prior art are also subject to the disadvantage, when they operate in this manner, of producing more and larger clinkers, as the fuel bed is always very deep, and with a deep fuel bed it is difficult, and practically impossible, to force the air for combustion through the fuel bed.

Such a, deep fuel bed also produces spirals or trees of `coke in the bed, which break up in large lumps, forming the large cracks in the fuel bed, through which all of the air flows, instead of being applied uniformly to the coal bed for uniform combustion.

to escape through to the top of the fuel bed,

without mixing with the carbon in the coal.

i' Of course, this type of operation of the devices of the prior. artis also very wasteful of fuel, as the carbon dioxide will at times amount to eight percent, andthen run to fifteen or twenty perand thereafter decent, and then on to smoke;

all in one run of crease again to eight'percet,`

As the devices of the prior artl'cause an overthis is responsible for the user endeavoring to change the coal feed to try to make it hold the proper temperature. Naturally the user thinks he is feeding too much coal when the room temperature is over-run. When the user cuts down the coal feed, the stoker is then not able to handle the job of heating the rooms on a colder day. In order to get sufficient heat on a colder day, the user then incre-ases the coal feed, and the result is that the stoker is never in proper adjustment.

ItA is my experience that thirty-five percent more coal is used in the dethe supply of air was also shut down, and

combustion, and smoking 'Y from twenty-live. to

off;

vices of the prior art, and I have found that in a standard stoker, which had been installed for two and one-half years, the coal consumption was reduced approximately one-third by the installation of the system embodying the present invention, and the over-run of the room temperature was so reduced that it was imperceptible to me, even during the Spring and Summer, when it is most diiicult with a coal stoker to regulate the heat required.

One of the objects of the present invention is the provision of an improved coal stoker sys` tem in which provision is made for adjustment of the amount of air supplied for combustion to that required for the furnace under dliferent operating conditions.

Another object of the invention is the provision of an improved coal stoker system inlwhich .the foregoing disadvantages of the prior art devices, such as smoking, formation of soot, temperature over-run, wasteful consumption of coal, and other disadvantages are eliminated.

Another object is the provision of an improved coal stoker system in which the amount of heat required for a room demand is adapted to be anticipated by the controlling devices and the heat generated in the furnace so adjusted to the demand that there is practically no over-run of the room temperature beyond that at which ,the thermostat is set.

Another object of the invention is the provision of an improved heating system which is adapted to be operated with a relatively thin re-bed by means of which the waste of coal is eliminated and better operation and combustion facilitated through the avoidance of a deep bed of coals, which have a tendency to form cracks and holes that pass the air supplied to the bed without the uniform air distribution' which is necessary to ecient combustion.

Another object of the invention is the provision of an improved coal stoker system which is adapted to operate smoothly and uniformly and to maintain a substantially uniform room temperature with a more-'emcient consumption of coal and less heat losses than the devicesof the prior art.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the `several views.

Referring to the four sheets of drawings:

Fig. 1 is a diagrammatic side elevational view of a c'oal stoker system shown in connection with a-hot air furnace embodying the invention, the furnace and .certain other parts of the'system being shown in vertical section; l

Fig. 2 is a top plan lview of the diagrammatic installation of Fig. 1, with the furnace housing in section;

Fig. 3 is a larger fragmentary view of the motor mounting and the air damper, by means of which an adequate supply of air is assured for the bed of coals, after the stoker feed has been turned Fig. 4 is afragmentary end elevational view of one end of the motor and driving mechanism, with the'housing partiallybroken away, to show an 'electric heating element;

Fig. 5 isfafragmentary sectional view, taken 'through a thermostatically actuated variable di- 'a1'neter pulley, taken on the vertical plane of the line 5-5 of *.Fig'.` 4, looking in the direction of the arrows;

Fig. 6 is a fragmentary view, including a wiring diagram for the motor control;

Fig. '7 is a view similar to Fig. 1 of a modification in which the thermostat of the variable diameter pulley is subject to the action of heated air from the plenum chamber of the furnace;

Fig. 8 is another view similar to Fig. 1 of a modification in which a fixed thermostat is subjected to heat from the air in the plenum chamber, by means of a copper extension tube and a bulb located in the plenum chamber;

Fig. 9 is an axial sectional view, taken through a spring pressed variable diameter pulley, which may be utilized for the driven pulley in certain embodiments of the invention;

Fig. 10 is a fragmentary end elevational view i employing coal stokers. such as hot water boilers; i

steam boilers, vapor systems, etc., in which case the thermostatic control may be connected' to be actuated by the heat of the water, vapor, or steam in the boiler, instead of the air in thew plenum chamber 23.

The furnace 2| is. provided with a retort 2l of suitable construction for containing the firebed, and the furnace casing 22 is provided with the usual cold air inlets 25 and the hot air' outlets 26 leading from the frusto-conical bonnet 21.`

A furnace retort 24- communicates through a suitable coal feed tube 28 with a coal hopper 29, having cover 30, and the coal in hopper 29 descends by gravity into engagement with a suitable feed screw 3| in the coal feed tube 28. I'he retort 24 is also in communication with an air supply tube 32, leading from a centrifugal blower 33, which is provided with a drive shaft 34, having a suitable'centrifugal impeller in the housins 35. v

The inlet of the centrifugal blower 33'may be at either or both ends ,38, 31 of the housing, and the bearing for the shaft 34 at the end 36 of the housing is preferably located inside the housing so that, the shaft does not protrude, and a centrally located inlet opening 38 may be provided with a closure 39 for controlling the supply of air to the blower 33.

The outlet 40 of the centrifugal blower 33 is. of course, connected with the air tube 32.

The stoker includes a suitable base 4I, which carries the blower 33 and also carries a gear 'case l42, provided with a bearing for the blower shaft 34, and with suitable speed reduction gears for driving the coal feed screw 3l.

'I'he shaft Il may extend through the gear case 42 and be provided with a thermostatically conconstant speed` motorI of `any standard construcj tion, adapted to maintain a substantially constant speed for the loads for which it is conthe motor 41.

` lever 96 by a pin 91. Damper radially structed, and the motory 41 is preferably provided with a base 49, which'may be secured upon a supporting plate 49.

The supporting plate 49 is provided with a pairvof depending apertured lugs 50 adapted to receive a stub shaft which is mounted in the bifurcated end lugs 52 of a motor-supporting bracket 53.

The bracket 53 lmay be iixedly secured toa frame member 54 carried by the base 4 I', and thus the motor 41 is pivotally supported on the base for the purpose of'maintaining the beltV 44 ina taut condition.

The motor pivot shaft 5| is preferably centrally located under the motor, or it may be located slightly to one side, to utilize the motor weight, to exert a pull on the belt 44. When the i motor support hasits pivot centrally located/unengaging the eye on the arm 55,v providing a pivotal connection. The spring 56 may be provided of the adjustable nuts and adjustable predetermined tension for urging the motor in a clockwise direction about the axis of the shaft 5| and maintaining a tension on the belt 44. l

. The stub shaft 5| is preferably iixedly secured to the, apertured lugs 50 androtatably mounted in the bracket 53 so that the shaft rotates with At one `end the shaft 5| is proyided with a crank arm 90, which is pivotally secured by a pin 9| to a connecting rod 92. The connecting eye screw, with a 94 at eacnend and fastened necting rod 92 may be adjusted.

The yoke 93 is pivotally secured to a damper lever 95 is pivotally mounted on the lower housing 35 by a pin 98, and it preferably carries a damper disc 39. The damper or air valve 39 is adapted to slidably engage the air inlet 39 of the blower housing' 35, and thus the tilting movementof the motor is adapted to control the movement of the damper 39 through. the intermediaryof the levers 90 and 96 and connecting rod 92.

'The driven pulley 43 on the shaft 34 is preferably a thermostatically controlled variable diameter pulley of the type shown in Fig. 5. This pulley may be any one of a number of different constructions disclosed in my prior applications, Case 1 Patent No. 2,2%),9'1illed March 15, 1938, of which this is a con nuation-in-part or Case 2. Serial No. 313,673, iiled January 13, 1940, of which Fig. 5 is exemplary.

The'variable diameter pulley preferably includes a pairI of relatively movable pulley sections |0|', |02, each of which is provided with a y extending ange |03, -|04, having opposed frustoconical belt-engaging surfaces |05, |06.` ,i

The pulley section |0| has an elongated cylindrical hub |01,-

section |02 has an elongated tubular habi".

having a cylindrical bore I|0 for slidably engaging the hub |01.

The tubular hub .|09 maybe provided with a pair of axially extending slots which are adapted to pass the legs of a U-shaped member ||2 which are attached to the inner hub |01. forming a frame for the support of a bellows thermostat H3.

The legs of the U-shaped member I|2 are ilxedly secured to the hub' |01 by screw bolts fi I4 passing through theselegs and threadedv into threaded bcresin hub m1.

A stop member ||5 may be mounted on the bolt ||4 and clamped against each leg of the U-shaped member ||2 for the purpose of limiting the movement'of the sections |0|, |02. Each stop member IIB has a slot ||6 for bolt ||4 and a pair of inwardly extending flanges ||1 for engaging an end plate I9.

The rotation of the pulley section |02 with respect to pulley section |0| is limited by inter-engagement between the wali's of. the slot III and the U-shaped member ||2, but sliding movement between these sections is permitted and is controlled by means of the thermostat I3.

The thermostat I I3 preferably comprises a corrugated metallic bellows, having both ends closed,

and the bellows is iilled with a thermally expansible fluid having a high coeilicient of thermal expansion. 'Ihe bellows has one end closed by a plate ||9, which has a threaded stud |20 passing through the U-shaped memberv I I2,'and secured therein by a plurality of nuts |2|.

The other end of the bellows is closed by the plate IIB, which projects beyond the periphery of the bellows and is of suillcient size to engage rod 92 preferably-has threaded adjustable ends, which are secured in a threaded bifurcated yoke 93,

v by a lock nut 95 so that the length of the conthe annular end ||2 of the tubular hub |09. The variable diameter pulley 43 is shown at the position of maximum diameter which it assumes.

when the bellows I|3 expandsunder influence of heat and forces the two sections closer together.

To do this the bellows reacts against the U- shaped member II2, which'is carried by the pulley section |0|, and its plate lI I8 engages the end |22 of the pulley section |02 and forces it toward the left in Fig. 5. When the'bellows cools, it is adapted to permit the belt 44 to force the pulley sections |0|, |02 apart, which permits the belt to ride farther down into the groove between 'the frusto-conical surfaces |05, |06, to decrease the effective diameter of the pulley 43.

'I'he characteristics .of the bellows and pulley sections and belt may be made suoli that the speed of rotation of the pulley 43, when driven by a constant speed 1motor 41 and an oordinary pulley, varies in proportion to the temperature of the expansible fluid in the bellows I I3.

hich is nxedly secured to the' -shaft 34 by means of' a set screw |00. The pulley The speed of rotation increases as the temper- -ature of the bellows ||3 increases.

The present variable diameter pulley 43 may be controlled by the temperature. of the. air in the plenum chamber, by means of the arrangement shown in Figs; 5 and 6. In this embodiment the thermostat of the pulley 43 is surrounded by a housing |23, which is-carried by the basev |24, which has an enlarged aperture |25, surrounding the hub|09 (Fig. 5.)

The housing may be madeA of insulating vmaterial, and it may support a porcelain cylinder or `spool |20, about which there is wound helically a plurality of coils of resistance wire |21, the coils already being in the form of a small helix, in

order to increase the length of the resistance wire.

"The resistance coils |21 are adapted to 'used As the temperature of as heating coils, and are provided with a plurality of taps |28, |29, and |30, and the number of taps may be increased as desired, from three to four, five, six, or any number desired, for-the purpose of increasing the steps or increments of resistance used in controlling the heat applied to the thermostat.

The number of taps shown is merely to be regarded as exemplary of one form of the invention.

The taps |28-|30 from the resistance divide the resistance |21 into two sections |3| and 32, as shown in the wiring diagram of Fig. 6. The numbers applied to the taps have also been used for the conductors of this diagram, and M indicates the constant speed electric motor 41.

The bonnet 21 or boiler o f the furnace is provided with a pressure responsive or thermally responsive switch |34, having a plurality of contacts adapted to be closed successively as temperature increases in the bonnet. For example, the switch |34 may include a bellows communieating with the thermal bulb |35 and actuating a movable switch arm |33, which is connected t3 the conductor |31.

The switch 34 has a pluralityvof fixed contacts, one of which is connected to the conductor |28, and the second one to the conductor |30.

The conductor |31, connected with the switch arm, leads to one side of the 110 volt electric light circuit |38. The variable diameter thermostatic pulley unit is shown at 43 in the diagram in position so that its thermostat is subjected to the heat from the heating element |21. The switch arm `|33 is provided with anl arcuate contact |4|, which may connect one of the contacts or both of them.

The electric motor 41 has one 0f its terminals connected by conductor |39 to the power circuit |40, and the other terminal connected by a conductor |42 to a room thermostat |43, or to suitable relays in combination with the room thermostat. The other conductor |36 from the Irelays or room thermostat is connected to the other terminal 38 of the power line. Y

The operation of this circuit is as follows. It should be understood that the controlling switch |34 may be either a thermally responsive switch, subjected to the heat of the plenum chamber, or subjected to the heat of the water, or heat f in the boiler, or it may be a pressure responsive switch, subjected to the pressure in the boiler. Normally the thermostat ||3 of the variable diameter pulley 43 is cold, because the heaters 3|, |32 are de-energized.

The pulley 43 has its sections |0|, |02 far apart, andthe diameter of the pulley 43 is at a Aminimum because the belt 44 is riding down closer to the shaft 34.

When the furnacefis in operation, the energization of the motor 41 is controlled by the room thermostat and Asuitable relays |43, and ademand for heat in the room causes the energization of the motor 41, whiph drives the shaft 34 at a high speed because the pulley 43 has asmall diameter.-

Thus the motor 41 drives the screw 3| to supply coal, and the blower 33 to supply air, both at high speed.

the air in the plenum chamber increases, or as the temperature of thev water in the boiler increases, or as the pressure 1 to 6 is as follows:

The first movement of the switch arm |33 connects the contact |4| with conductor |28 and energizes the heater |3|. heats the thermostat ||3 and causes the pulley sections |0|, |02 to approach each other, increasing the effective diameter of the pulley 43, and decreasing the speed of operation of the coal feeding screw 3| of the air blower 33.

As the temperatures or pressures mentioned above increase further, the arm 33 is moved further into contact with the fixed contact connected to conductor |30, also energizing the heater |32, which heats the thermostat ||3 to a still higher temperature to press the pulley sections |0|, |02 together to the position of Fig. 5. y

'I'his increases the effective diameter of the pulley 43 still further, and causes the screw 3| and the blower 33 to be driven at a still lower speed, decreasing `the feeding of coal and the supply of air.

It should be understood that any number of additional heating element sections may be used with additional conductors and contacts on the controlling switch |34. Thus, the feed of the air and coal may be decreased as the furnace arrivesv at a higher temperature.

The operation of the complete system of Figs. The controlling circuit just described is adapted to regulate the cold air feed according to the furnace temperature, steam pressure, or water temperature. For any coal feed regulation from a high coal feed to a low feed, air for combustion must also be properly regulated.

The coal feed may be regulated by the speed changes which are brought about by the thermostatically controlledpulley driving the feed screw through the intermediary.- of the gears in the gear case 20. As the diameter4 of the 4pulley 43 is varied, the length of the belt 44 being constant, an increase in the diameter of the pulley 43 results in a pulling of the motor toward the left, or counterclockwise, in Fig. 1, against the tension of spring 56.

The belt 44, riding out farther toward the periphery of the pulley 43, pivots the motor 41 with its shaft 5|. This causes the control crank to move the connecting rod 92 toward the left in Fig. 2, which moves the air damper 39 toward the left to the position of Fig. 2, opening the` air inlet 38 as the-speed of operation of the shaft 34 decreases.

When the room thermostat calls for heat, starting the stoker, the furnace being cold, the stoker coal `feed'is operated at high speed and the air shutter is nearly closed. As the furnace temperature of a warm air furnace reaches degrees F., for example, theheating element |3| is energized bythe closing of. electric contacts of the controlling element |34, 'and the thermo- :statically controlled pulley 43 changes its pitch of the steam or vapor in a steam or vapor system increases, the controlling element |34 is actuatedlto move the switch arrn |33.

` ley 43 expands it pulls the motor 41 toward the diameter from small to large, thus reducing the speed of the shaft 34 and cutting down the speed of coal feed by the screw 4|.

At the same time the blower speed is cut down,

I thus delivering less air.. and in this instance the stoker would smoke unless some provision were made for supplying a suiiicient amount of air.

In the present case, this is taken care of by `the opening of the blower inlet 38 by means of thedamper 39.- Thisis brought about by the fact that as the thermostatically controlled p ulblowerV and moves the levers 30 and 96 (Fig. 3)

The-heater |3| then e counteract the tendency of .ish the air supply.- Since f ment |34 is provided with a plurality of contacts,

. blower speed.

ingy elements |32- l not effect a `complete l closure the shaft 46 by means of other.

e. 03 are carried by 1I and 14. The hub ina clockwise direction to open the damper 39.

This permits the blower to supply a proper amount cause the blower speed of operation of the blower decreases, to

the blower to diminthe controlling eleseveral stagesl of speed of operation may be provided, and in every case the air will be properlyregulated, as the air .shutterV or damper 39 will be moved according to the coal feed and one or the most impe ant advantages of'this n mode of operation is' that the stoker is always stopped by the'thermostat or furnace limit control when lt is operating on low coal feed, with the blower inlet nearly wide open. This is advantageous because the blower inlet` is then opened much farther than it is in the stokers of the prior art, and the natural' draft of the flue is adapted to clear away all Csmoke and soot when the stoker is shut down. Then as the fur'- nsce .cools naturally; the thermostat or the thermostatically controlled pulley cools also, as the electric current is cut off from the electric heatand iii, successively. The blower inlet is then slowly closed, which reduced threaded portion adapted to slidably receive a spring seat 16, which is secured in adjusted position by a nut and lock washer 11.

The "spring seat 16 may consist of a metal member having a bore 18 for receiving the reduced portion 15 of the hub 65, and there may be a key 10 and a. key-way 80 for preventingthe relative rotation between the spring seat .16 and banks the nre automatically. This blower inlet movement of the motor then closes the air dampbecause, as lthe thermostatic element Itshould be noted that the air damperdoes of the air inlet 38, but leaves the air inlet 38 sumciently open to provide asupply of air for the next high nre start.

This is accomplished by having the damper 39 spaced from the spring-pressedvariable diameter pulley |00 of` the type shown in Fig. 9. l

The'pulley |00 may be ofthe type shown in Fig. 9, in which this construction of the pulley is belt tension spring 56 to force Y The 44.0 opening 38. This control system is a marked advantage over the systems of it is adapted to be used to s, this is s modification in which the shaft 34 is provided with an ordinary V pulley, :and the shaft 46 is provided with .a1

shown in detail. This pulley preferably includes a pair of relatively movable pulley sections 60 and 6| each of which ceiving the belt 44.

Thepulley section maybe provided with an elongated hub 65 and may be `fixedly mounted on a cylindricalbore 66 and a set screw 61. This hub 6l is provided with a suitable slot 0l and a key 60 forslidable engagementin a key-way 10 formed in the cylindrical bore 1|.of the hub 12v of the-pulley lsection 4|.- j

.Hub .12 is also elongated so that the two pulley sections have long'complementary bearing surfaces" and 65 engaging each other and' preventing any tilting of the sections relative to each 'rnerrusto-conisi beitseneaging surfaces n, the radially extending flanges l5 may be provided with' a is provided with one of the 4opposing .frustogconicai surfaces 02, 63, which l form the substantially V-shaped groove 54 for rethe member 15. The outer edge of the spring ed to retain the coil spring 482 in concentric relation with respect to the hub 65.

The other end of the coil spring 82 engages the radial flange 14 and surrounds a cylindrical portion 83. `The spring 62 urges the two pulley sections and 6| togethen'butthe pulley sections are adapted to be forcedapart by suflicient tensionplaced on the belt 44, which wedges its-way between the surfaces 62, 63, when provided with suicient tension, and forces the sections 60, 6| apart.

In this embodiment the motor is again pivotally'mounted and urged in a counterclockwise direction by a motor tension spring 56, but the position of the motor is controlled by means of a thermostatically controlled bellows |50, one end of which is xedly mounted on a. bracket |5I.

The other end of the bellows is connected by an adjustable length connecting rod |52 to a pivot pin |53 carried by a motor bracket |54. The bellows |50 is connectedby a copper tube |55 to a thermally responsive bulb |56 or a source of boiler pressure and, a's before described, the element |56 may be actuated responsive to `bonnet temperature, water temperature, or boiler on whether the system is pressure, depending a, hot Water boiler,

applied to a hot air furnace,

Aor a steam or vapor system.

system is similar to that 'Ihe operation of this previously described, except that no heating eleinents are required, since the bellows |50 may be directly connected to the lcontrolling element |56,

.which is subjected to furnace temperature, water -ulated coal and air feed from maximum Vspeed at low furnace temperature, boiler temperature, or boiler pressure to slow rate of feed at high furnace temperature, furnace temperature, or

boiler temperature. p, The variation isbrought about in thiscase by -means of the thermostat |50, as follows: As the bellows |50 expands, the motor 41 rocks in\a clockwise direction, and due to the belt 44 being of constant length, the belt is drawn farther into the groove of the variable diameter pulley |00, decreasing the effective diameter of the driving pulley, and decreasing-the speed of operation of the coal feed and blower, with increase in temperature or pressure. The inlet to the blower is again opened as the coal feed is cut down, and the coal lfeeding is stopped. In this case the tilting of the motor causes the belt 44 to ride out farther in the groove 64 of the variable diameter pulley |00 as the temperature or pressure at the furnace increases. that of Fig. l.

Referring to Fig. 11, this is a modication in which the thermal `bulb is not subjected to the temperature of the air in the furnace, but is responsive to the temperature of the the furnace itself.

Referring to Fig. 7, this is a modification sinn- The operation is similar to bonnet of lar to Fig. 1, in that the shaft 34 is provided with a. thermostatically controlled variable diameter pulley 43, but no electric heating elements are provided. Instead, the system is -provided with an auxiliary blower |60, which may also have a thermostatically controlled variable diameter pulley |6|, driven by a belt |62 from a pulley on the motor shaft 46, and the blower |66 is adapted to circulate the air through the plenum chamber 23.

The pulleys |6| and 43' may both be subjected to hot air from the plenum chamber 23 by means of a conduit'l |63 leading from the plenum chamber to an air chamber |64 surrounding the thermostat of the pulley 43 and an air chamber |65 surrounding the thermostat of the pulley |6|.

In this case both the thermostats of the variable diameter pulleys 43 and |6| wiil be controlled by the temperature of the air in the plenum chamber, since air is conducted directly from the plenum chamber to these thermostats.

The speed of feed of the coal and the air of combustion will be decreased as the temperature of the air in the plenum chamber increases, and the speed of circulation of the air through the plenum chamber will be .increased as the temperature of the air in the plenum chamber increases.

The present invention is adapted to decrease the consumption of coal and to effect better combustion in stoker operated furnaces or boilers. y

There is never a deep coal bed left in the furnace, and the coal bed may vary from approximately three inches, when there is a low bed, to six inches deep during the high ring period.

After the coal vbed has reached a thickness of, for example, six inches on the high firing period, the stoker is cut to low feed at a vtemperature of, for example, 125 degrees F. of the warm air in the'plenum chamber, or, for example, at two pounds or five pounds steam.

Then the coal, which has been brought in at high feed, is burned up, and the thickness of the fire bed is reduced before the limit switch setting is reached. On a warm air gravity circulation installation, the limit switch is usually set at about 300 or 350 degrees F.; on a ve pound steam installation, the stoker is cut to low feed in approximately two pounds steam pressure; and on a hot water installation, with a maximum limit switch setting of 180 degrees F., the Stoker is cut to low feed at 125 to 140 degrees F., depending on the load on the boiler.

'I'he result is that it is practically impossible to bring the furnace or boiler temperature up to the limit switch setting because, as the coal feed and air feed is reduced, the excess coal, which is forced into the furnace while on high feed, is

The present invention also hasl the advantage that fresh or green coal is coming, up

bed; and there is always suiiicient fuel to maintain the pilot or kindling flre, in the retort.

According to the present invention, the coal feed is at all times feeding some coal on low setting, which eliminates 'the bad operating results that are inherent in the devices of the prior art.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to bev limited to the precise details of `construction set forth. but desire' to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1.` In a stoker controlling system,- the combination of'a driving motor with a coal feeding means adapted to be driven by said motor, a -blower for supplying air forcombustion, pulley means for driving said blower and coal feeding'means, pulley means driven by4 said motor at substantially.

constant speed, one of said pulley means comprising a variable diameter V pulley interposed between the motor and the coal feed and blower, and thermostatic means for directly controlling the effective diameter of said pulley, whereby the rate of feed of coal may be controlled substantially proportionally to the temperature of said thermostatic means. y

2. In a fuel supply system for stokers, the combination of a retort with a coal feeding member for feeding coal to said retort, an air supply conconsumed before the limit temperatures are l reached. In other words, the small amount of coal fed 'on low lire, plus the surplus fed on high, will be consumed, and the re bed is reduced to a point where itrwill carry the heating loadV on low fire and when shut down there is lef t only a -shallow fuel bed. Therefore, there is no overrun, and practically no smoke or soot, with an installation made according to the present invention. l

The present invention results in the regulation of the coal and air feed according to the demands on the furnace. This invention also eliminates the tendency of some of the devices of the prior art to form clinkers, which melt into a slag and run down into the retort, closing the air ports, and burning on the end of the worm,

duit for providing a supply ofv air for combustion, a driving motor for driving said blower and said coal feeding member. said motor being movably mounted upon a support, a pair of V pulleys carried by the shafts of said blower and motor, one

l 'of said V pulleys being a variable diameter pulley having a pair of movable sections provided with frusta-conical surfaces for engaging the edges of a. wedge-shaped belt, and thermostatic means for controlling the effective diameter of said variable diameter pulley whereby the speed of clz'iveA of said blower and fuel feeding member may be Y varied responsive to temperature conditions while driven with a constant speed motor.

' 3. In a fuel supply system for stokers, the com-v bination of a retort with a coal feeding member for feeding coal to said retort. an air supply conduit for -providing a supply of air for combustion. a driving motor for driving 'said blower and said coal feeding member, said motor being movably mounted upon a support, a pair of V pulleys carried bythe shafts of said blowerand motor respectively, one of said V pulleys being a. variable diameter pulley having a pair vof movable sections provided with frusto-conical surfaces for engaging the edges of a wedge-shaped belt, and ther mostatic means for controlling the effective diameter of said variable diametervpulley whereby the speed of drive of said blower and fuel feeding member may be varied responsive to temperature conditionsfwhile driven with a constant speed motor, said thermostatic means being carried by the same shaft which supports said variable diameter pulley and acting on one section to move it relativeto the other.

4. In a fuel supply system -for stokers, the combination of a retort with a coal feeding ymember for feeding coal to said retort, a blower and an air supply conduit for providing a supply of air for combustion, a driving motor for driving'said blower and said coal feeding member, said motor being movably mounted upon a support, a pair of V pulleys carried by the shafts of said blower and motor, one of said V pulleys being a variable diameter pulley having a pair of movable sections provided with frustc-conical surfaces for engaging the edges of a wedge-shaped belt, and thermostatic means g for controlling the effective diameter of said variable diameter pulley and the position of said motor, whereby the speed of drive of said blower and fuel feeding member may be varied responsive to temperature conditions while driven with a constant speed motor, valve means adapted to control the now of air in said air conduit and operative connecting means between said valve means and said motor whereby the movement of the motor acts to control the opening or closing of said valve means tending to provide an sure responsive switch having a plurality of contacts for controlling an electric heater, and a thermostat for controlling the relative positions of the parts of the variable diameter V pulley, v

`said thermostat being controlled by said heater.

'7. In a fuel supply for stokers, ,the combination of a retort with a c'oal feeding member for feeding coal to said retort, a blower for providing a. supply of air for combustion to said retort, a driving motor for driving said blower and said coal feeding member, said blower and coal feeding member having a common driving shaft, a lV pulley mounted on said common driving shaft,

' a V pulley mounted on the motor shaft and a y ,wedge-shaped belt connecting said V pulleys, one

of s'aid V -pulleys being a variable diameter pulley having a pair of movable sections provided with frusto-conical surfaces for engaging the edges of a wedge-shaped belt, valve means for controlincreased supply of air when the pressure of said j blower is diminished by reason of a lower speed.

5. In a fuel supply for stokers, the combination of a retort with a coal feeding member for feeding coal to said retort, a blower for providing a supply of air for combustion to said retort, a driving motor for driving said blower and said coal feeding member, said blowerI and coal feeding lmember having a common driving shaft, a V pulley mounted on said common driving shaft, a V y pulley mounted on the motor shaft and a wedgeshaped belt connecting said V pulleys, one ofsaid V pulleys being a variable diameter pulley having a pair of movable sections provided withfrustoconical surfaces for engaging the edges of a wedge-shaped belt, valve means 'for controlling the flow of the air 0f combustion supplied by said blower, and regulating means controlled responsive to the condition of heat generation of the heater and arranged and constructed to decrease the speed of operation of said common drive shaft by changing the distance between said frustoconical surfaces and whereby thev ow of combustion airto the retort is decreased and the-rate of feed of coal tothe retort is decreased as the heater reaches a predetermined conditionwith respect to the genl eration and storage` of heat energy at the heater.`

' 6. In a fuel supply for stckers, the combination of a retort with a coal feeding member for feeding coal to said retort, a blower for-providing a supply of airfor combustion to said retort, a. driving motor for driving said blower and said'coal feeding member, said .blower and coal feeding member having a common driving shaft, a V pulley mounted on said common driving shaft, a V "pulley mounted on the motor shaftand a wedge-shaped belt connecting said V pulleys, one

of said V pulleys being a variable diameter pulley having 'a pair of movable sections provided with {ruste-conical surfaces for engaging the .edges of a, wedge-shaped belt, valve means for controlling ,the flow of the air of combustion supplied by said blower, and regulating means controlled responsive to the condition of heat generation of the heater and arranged and constructed to decrease the speed of operation pf said common drive shaft by changing the distance between said frusto-conical surfaces and to move said valve means whereby the flow of combustionv air to the retort is decreased and the rate of feed of coal to the retort is decreased as the heater reaches a predetermined condition with respect to the generation and storage of' heat energy at the heater, said regulating means comprising a presling'the flow of Ithe air of combustion supplied by said blower, and regulating means controlled responsive to the condition 'of -heat generation of the heater and arranged and constructed to decrease the speed of operation of said common drive shaft by changing the distance between said frusto-conical surfaces and to move said valve means whereby the ow of combustionlair to the` retort is 'decreased and Tthe rate of feed of coal to the retort is decreased as the heater reachesv a predetermined condition with respect- -to the generation and storage of heat energy at the heater, said regulating means comprising a thermostatic switch subjected to heat from the heater :and controlling an electric heater, and a thermostat heated by said electric heater for controlling the relative positions of the parts of the variable diameter pulley. c

8. In a fuel supply system for stokers, 'the combination of a retort with a coal feeding member for feeding coal to said retort, a blower and an air supply conduit for providing a supply of air for combustion, a driving motor for driving said blower and said coal feeding member, said to move said valve means I,

vso

motor being movably mounted upon a, support, a pair of V pulleys carried bythe shafts of said blower'and motor, one of said V pulleys being a variable vdiameter pulley having a pair of movable sections provided with frusto-conical surfaces for engaging the edges of a wedge-shaped A. belt, and thermostaticmeans for controlling the',4

effective diameter of -said variable diameter pulley and' the position of said motorl whereby the speed of drive of said blower and fuel feeding member may. be varied responsive to temperature conditions while driven' with a constant speed motor, valve means adapted tocontrol the flow of air in said air conduit and operative connecting means between lsaid valve means and said motor whereby the movement of the motor acts to control the opening or closing of said valve means to provide an increased supply of air when the pressure of said blower is diminished by reason of a lower speed, said thermostatic means comprising a thermostat adapted to act on one pulley section and react on .the other pulley section to effecta relative movement between the movable sections of the variable diameter puliey.

9. In a fuel supply system for stokers, the combination of a retort with a .coal feeding member for feeding coal to said retort. a blower and an air supply conduit for providing a supply of air for combustion, a-driving motor for driving said blower and said coal feeding member, said motor being movably mounted upon a support, a pair of v pulleys carried by the shafts of said blower and motor, one of said V pulleys being a variable diameter pulley having a pair of movable sections provided with frusto-conical surfaces for engaging the edges of a wedge-shaped belt, and thermostatic means for controlling the effective diameter of said variable diameter pulley and the position of said motor whereby the speed of drive of said blower and fuel feeding member may be varied responsive to temperature conditions while driven with a constant speed motor, valve means adapted to control the ow of air in said air conduit and operative connecting means between said valve means and said motor whereby the movement of the motor acts to control the opening or closing of said valve means to provide an increased supply of air when the pressure of said blower is diminished by reason of a lower speed, said thermostatic means comprising a thermostat adapted to act on one pulley section and react on the other pulley section to eiect a relative movement between the movable sections of the variable diameter pulley, said thermostatic means being enclosed in a housing, and an electric heater enclosed in said housing for heating said thermostatic means responsive to the energization of said electric heater.

10. In a. fuel supply system for stokers, the combination of a retort with a coal feeding member for feeding coal to said retort, a blower and an air supply conduit for providing a supply of air for combustion, a driving motor for driving said blower and said coal feeding member, said motor being movably mounted upon a support, a

- pair of V pulleys carried by the shafts of said blower and motor, one of said V pulleys being a variable diameter pulley having a pair of `movable sections provided with frusto-conical surfaces for engaging the edges of a wedge-shaped belt, and-thermostatic means for controlling the effective diameter of said variable diameter pulley and the.position of said motor whereby the speed of drive of said blower and fuel feeding member may be varied responsive to temperature conditions while driven with a constant speed motor, valve means adapted to control the iiow of air in 4said air conduit and operative connecting means between said valve means` and said motor whereby the movement of the motor acts to control the opening or closing of said valve means to provide an increased supply of air when the pressure of said blower` is diminished by reason of a lower speed, said thermostatic means comprising y able sections provided Awith frusto-conical sur-l faces for engaging the edges of a wedge-shaped belt, and thermostatic means for controlling the eective diameter of said variable diameter pulley and the position of said motor whereby the speed of drive of said blower and fuel feeding member may be varied responsive to temperature conditions while driven with a constant speed motor, valve means adapted to control the flow of air in said air conduit and operative connecting mean's between said valve means and said motor whereby the movement of the motor acts to control the opening or closing of said valve means to provide an increased supply of air when the pressure of said blower is diminished by reason of a lower speed, said thermostatic means comprising a thermostat adapted to act on one pulley section and react on the other pulley section to effect a relative movement between the movable sections of the variable diameter pulley, said thermostatic means being enclosed in a housing, and an electric heater enclosed in said housing for heating said thermostatic means responsive to the energization of said electric heater, and switch means controlled by a pressure responsive i device responsive to the pressure of a boiler for controlling the energization of said heater.`

12. In a fuel supply system for stokers, the combination of a retort with a coal feeding member for feeding coal to said retort, a blower and an air supply conduit for providing a supply of air for combustion, a driving motor for driving said blower and said coal'feeding member, said motor being movably mounted upon a support,

a pair of V pulleys carried by the shafts of said blower and motor, one'of said V pulleys being a variable diameter pulley having a pair of movablev sections provided with frusto-conlcal surfaces for engaging the edges of a wedge-shaped belt, and thermostatic means for controlling the eiective diameter of said variable diameter pulley and the a thermostat adapted to act on one pulley sec-` tion and react on the other pulley section to effect a relative movement between the movable sections -of the vvariable diameter pulley, said 'thermostatic means being enclosed in a housing,

and an electric heater enclosed in said housing for heating said thermostatic means responsive to the energization of said electric heater, and a second thermostatic means located to be actuated responsive to temperature conditions at the heater for controlling the energfzation of said first-mentioned thermostatic means. l

11. In a fuel supply system for stokers, Athe combination of a retort with a coal feeding member for .feeding coal to said retort, a blower and an air supply conduit for providing a supply of air for combustion, a driving motor for driving said blower and said coalfeeding member, said motor being movably mounted upon a support, a

pair of Vpulleys carried by the shafts of said blower and motor, one of said V pulleys being position of said motor whereby the speed of drive of said blower and fuel feeding member may be varied responsive to temperature conditions while driven with a constant speed motor, valve means adapted to control the iiow of air in said air conduit and operative connecting means between said valve means and said motor whereby the movementvof the motor acts to control the opening or closing of said valve means to provide an increased supply of air when the pressure of said blower is diminished by reason of a lower speed, and a. controlling device controlled responsive to the generation of a predetermined amount of heat energy at the heater containing said retort for controlling the action of said thermostatic means whereby the combustion is cut down as the heated condition of the heater increases to reduce the amount of over-run of temperature.

13. In a fuel supply for stokers, the combination of a retort with a coal feeding member for feeding coal to said retort, a blower for providing a supply of air for combustion 'to said retort, a driving motor for driving said blower and said coal feedingmember, said blower and coal feeding member having a common driving shaft, a V

' pulley mounted on said common driving shaft, a

heat generation of the heater and arranged and `constructed to decrease the speed of operation of said common drive shaft by changing the distance between said frusto-conical surfaces, whereby the rate of feed of coal to the retort is decreased as the heater reaches a predetermined condition with respect to the generation and storage of heat energy at the heater.

14. In a fuel supply for stokers, the combination of a retort with a coal feeding member for feeding coal to said retort. a blower for providing a supply of air for combustion to said retort, a driving motor for driving said blower and said coal feeding member, said blower and coal feeding member having a common driving shaft, a V pulley mounted on said common driving shaft, a V pulley mounted on the motor shaft and a wedge-shaped belt connecting said V pulleys, one of said V pulleys being a variable diameter pulley having a pair of movable sections provided with frusta-conical surfaces for engaging the edges of a wedge-shaped belt, and regulating means controlled responsive to the condition of` heat generation of the heater and arranged and constructed to decrease the speed of operation of said common drive shaft by changing the distance between said frusto-conical surfaces, whereby the rate of feed of coal to the retort is decreased as the heater reaches a predetermined condition with respect to the generation and storage of heat energy at the heater, said regulating means comprising a pressure responsive switch having a plurality of contacts for controlling an electric heater, and a thermostat for controlling the relative positions of the parts of the variable diameter V pulley, said thermostat being controlled by said heater. i

15. In a fuel supply for stokers, the combination oi. a retort with a coal feeding member for feeding coal to said retort, a blower for providing a supply of air for combustion to said retort, a driving motor for driving said blower and said coal feeding member, said blower and coal feeding member having a common driving shaft, a V pulley mounted on said common driving shaft, a V pulley mounted on the motor shaft and a wedge-shaped belt connecting said v pulleys, one of said V pulleys being a variable diameter pulley having a pair of movable sections provided with frusta-conical surfaces for engaging the edges of a wedge-shaped belt, and regulating means controlled responsive to the condition of heat generation of the heater and arranged and constructed to decrease the speed of operation of said common drive shaft by changing the distance between said frusto-conical surfaces whereby the rate of feed of coal to the retort is decreased as the heater reaches a predetermined condition with respect to the generation and storage of heat energy at the heater, said regulating means comprising a thermostatic switch subjected to heat from the heater and controlling an electric heater, and a thermostat heated by said electric heater for controlling the relative positions of the parts of the variable diameter pulley.

16. In a fuel supply system for stokersMthe combination of a retort with a coal feeding member for feeding coal to said retort, a blower and an air supply conduit for providing a supply l,of air for combustion, a driving motor for driving said blower and said coal feeding member, said motor being movably mounted upon a support, a pair of V pulleys carried by the shafts of said blower and motor, one of said V pulleys being a variable diameter pulley having a pair of movable sections provided with frusta-conical sureffective diameter and the position of said motor faces for engaging the edges of a wedge-shaped belt, and thermostatic means for controlling the of said variable diameter pulley whereby the speed of drive of said blower and fuel feeding member may be varied responsive to temperature conditions while driven with a constant speed motor, said thermostatic means comprising a thermostat adapted to act on one pulley section and react on the other pulley section to effect a relative movement between the movable sections of the variable diameter pulley.

17. In a fuel supply system for stokers, the

combination of a retort with a coal feeding member for feeding coal to said retort, a blower and an air supply conduit for providing a supply of air for combustion, a driving motor for driving said blower and said coal feedingl member, said motor being movably mounted upon a support, a pair of V pulleys carried by the shafts of said blower and motor, one of said V pulleys being a variable diameter pulley having a pair of movable sections provided with frusto-conical surfaces for-engaging the edges of a wedge-shapedbelt, and thermostatic means for controlling the effective diameter of said variable diameter pulley and the position of said motor whereby the speed of drive of said blower and fuel feeding member may be varied responsive to temperature conditions while driven with a constant speed motor.

said thermostatic means comprising a thermostat i adapted to act on one pulley section and react on the other pulley section to effect a relative movement between the movable sections of the variable diameter pulley, and an electric heater for heating said thermostatic means responsive to the energization of said electric heater.

18. In a fuel supply system for stokers, the combination of a retort with a coal feeding member for feeding coal to said retort, a blower and an air supply conduit for providing a supply of air for combustion, a driving motor for driving said blower and said coal feeding member, said motor being movably mounted upon a support, a pair of V pulleys carried by the shafts of said blower and motor, one of said V pulleys being a variable diameter pulley having a pair of movable sections provided with frusto-conical surfaces for engaging the edges of a wedge-shaped belt, and thermostatic means for controlling the eective diameter of said variable diameter pulley and the position of said motor whereby the speed of drive of said lblower and fuel feeding member may be varied responsive to temperature conditions while driven with a constant speed motor, said thermostatic means comprising a thermostat adapted to act on one pulley section and react on the other 4pulley section to eect-a relative movement between the movable sections of the variable diameter pulley, and an electric heater for heating v said thermostatic means responsive to the enermotor being movably mounted upon a support, a l

the shafts. of said pair of V pulleys carried by being a blower and motor, one of said V pulleys variable diameter pulley having a pair o! movable sections provided with frusto-conical surfaces for engaging the edges of a Wedge-shaped belt, and thermostatic means for controlling the effective diameter of said variable diameter pulley and the position of said motor whereby the speed of drive of said blower and fuel feeding member may be varied responsive to temperature conditions While driven with a constant speed motor, said thermostatic means comprising a thermostat adapted to act on one pulley section and react on r f the other pulley section to effect a relative movefor combustion, a driving motor for driving said blower and said coal feeding member. said motor being movably mounted upon a support. a pair oi V pulleys carried by the shafts of said blower and motor, one of said V pulleys being a variable diameter pulley having a pair of movable sections provided with misto-conical surfaces for engaging the edges of a wedge-shaped belt, and thermostatic means for controlling the effective diameter of said variable diameter pulley and the position of said motor whereby the speed of drive of said blower and fuel feeding member may be varied responsive to temperature conditions while driven with a constant speed motor, and a controlling device controlled responsive to the generation of a predetermined amount of heat energy at the heater containing said retort for controlling the action of said thermostatic means whereby the combustion is out down as the heated condition of the heater increases to reduce the amount of over-run of temperature.

WILLIAM w. HALLmAN. 

